This invention relates to a method for preparing a cyclic ring structure and more particularly, to a method for preparing strained cyclic disilanylene-acetylenes.
Various types of organic, metal organic, and inorganic materials are known which have unusual highly anisotropic and potentially useful electric, optical, and/or magnetic properties. Such materials are known to be useful in fabricating electrical conducting materials, semi-conductors, electronic devices, and electromagnetic or acoustic sensors. The utility of some of these materials is frequently limited by such factors as weight, mechanical fragility, fabrication problems, corrosion, scarcity, and high costs.
Electronconductive organic materials have properties which can overcome or minimize such problems, and have the capability to be easily fabricated into films, filaments, and other shapes. Some of these materials are simply an organic compound containing a conductive material therein, such as a metal or graphite. Others comprise organic material whose electrical conductivities are established by chemical doping with electron acceptor and/or electron donor dopants. In general, the materials susceptible of establishing such electrical conductivity are characterized by highly delocalized .pi.-electron conjugation, as may be found in most cyclic compounds or sometimes by .sigma.-electron delocalization which may be found in polysilanes as well as the Si-C heterocyclic compounds. Electron delocalization between Si--Si .sigma. bonds and .pi. systems has been established for conjugated polysilyl compounds containing unsaturated or aromatic groups. Such .sigma.-.pi. electron delocalization results in a strong ultraviolet absorption around 220-270 nm. Especially strong ultraviolet absorption at 250 nm has been found in the strained cyclic disilanylene-acetylene compound shown in Formula I. ##STR2## The compound of Formula I was obtained from the application of either heat or light to the nine-membered ring compound shown below. ##STR3## The compound of Formula I, because of its strong absorption in the near 250 nm wavelength, should have a high degree of .sigma.-.pi. electron delocalization and therefore a high potential for use as an electroconductive material as well as an optical material. In addition, possibilities exist that the ring of the cyclic molecule might be opened and the cleaved molecule polymerized through the use of Na, K, or t-butoxide. Further, like polysilanes, the compound of formula I should undergo conversion to silicon carbide when heated to high temperatures.